| Abstrakt: |
A series of CePd3Mx compounds (M = Na, Mg, Ca, B, Al, Ga, Si, Ge, S, Te, In, and Sn) has been synthesized and their structural, magnetic, and thermoelectric properties measured. The formation of an ordered CePd3M0.125 phase appears to be a gradual transition for elements from rows 2-4 of the periodic table while a miscibility gap appears to exist in the pseudo binary CePd3-CePd3M0.125 phase diagram for M elements from row 5. We report for the first time the existence of alloys with M = Te and S synthesized through a novel precursor approach, with the S-filled compounds showing an unusual contraction of the unit cell. The average valence of the Ce ions in CePd3Mx appears to be strongly correlated with both the electron count and filling fraction of the M elements, while the thermal conductivity reduction achieved through partial filling appears to saturate for M elements with masses above ∼25 amu and at filling levels above ∼5%. The combination of these effects results in a modest enhancement in the thermoelectric figure of merit from 0.07 to 0.11 at 100 K for samples filled with Mg and Ca at a nominal filling level of x = 0.02. Further modest increases may be possible using this approach if improved synthesis procedures can be developed. [ABSTRACT FROM AUTHOR] |
